SDM is a psychological device which transforms the thinking of dreams using free associations, thematic amplification and systemic thinking in order to create links, find connections and liberate/generate new thinking. Social dreaming was discovered by G. Lawrence in the 1980s when he was the director of the Tavistock Institute of Human Relations in London. The experience of the SDM in the field of ethnopsychoanalytical research and in particular in the field of history has enabled us to make important observations on how the matrix takes shape, what it is and what it represents in terms of the collective unconscious and hence the social unconscious. The Matrix creates culture: it is thus foundation element. From the rite or rituality, from the dream to the building of an identity and culture, the step is short. he Matrix is a container but it is above all a psychosensorial experience with an affective base which leads to the formation of a “structure process” that can be defined as the building of meanings by means of dreams. It enables us to represent “ideal anthropological structures” and so, in terms of group processes, give maximum facilitation to the capacity of the collective to accesses into knowledge.